Step-by-step driving-jack



Get. 17, 1967 A. REINMANN STEP-BYSTEP DRIVING-JACK 3 Sheets-Sheet 1Filed April 8, 1966 TORNEY INVENTOR mfred Remmann Oct. 17, 1967 RE|NMANN3,347,522

STEP-BY-STEP DRIVING-JACK Filed April 8, 1966 3 Sheets-Sheet 2 H53 QFIG.-

2 7 5 6 2 /s g 2/ I 35 2s INVENTOR Alfred Reinmann Oct. 17, 1967 R N3,347,522

STEP-BY-STEP DRIVING-JACK Filed April 8, 1966 3 heets- Sheet 3 INVENTORAlfred Reinmann Y- 4 A TORNEY United States Patent 3,347,522STEP-BY-STEP DRIVING-JACK Alfred Reinmann, Niederbipp, Switzerland,assignor to Werkzeugfabrik Selzach A.G., Selzach, Switzerland Filed Apr.8, 1966, Ser. No. 541,181 Claims priority, application Switzerland, Apr.28, 1965, 5,868/ 65 9 Claims. (Cl. 254-105) ABSTRACT OF THE DISCLOSURE Adriving-jack equipment for stepwise advancing a load along a support,including gripping heads operable by means of an actuating cylinder andhaving each at least one set of gripping jaws engageable with saidsupport, each set of said gripping jaws being loosely held in a cagebetween said support and a conical wedging surface for said grippingjaws.

This invention relates to a driving-jack equipment for stepwiseadvancing a load along a support, for instance a rod, a rope or thelike, the said equipment having a cylinder and a piston relativelydisplaceable by means of pressure fluid admitted to the cylinder, andconnected each to a gripping head. Prior driving or lifting jacks ofthis type serve for advancing working platforms, slip forms and the likealong scaffolding rods or poles. The gripping heads of the prior drivingor lifting jacks are not satisfactory for various reasons. The grippingelements are balls or jaws of segment-shaped cross section inserted intothe casing of the gripping head and urged against the conical end of thecasing by spring action. Gripping jaws of segment-shaped cross sectionare expensive whereas the driving force obtained with gripping balls isvery limited if excessive local pressure against the rod or pole andconsequently deformation of the latter is to be avoided. Further, it isdifiicult or impossible to actuate gripping jaws loosely inserted intothe gripping head by remote control means, but remote control of thegripping heads is necessary when double-acting jacks for producingdriving forces in opposite directions are required.

Gripping heads with sets of gripping balls inserted in cages and adaptedto be brought into an operable engaged position and into an inoperabledisengaged position by remote control are known, but the balls aredisadvantageous for the reasons set 'out above. it is a first object ofthis invention to avoid the drawbacks of all prior jack systems and toprovide sets of gripping jaws adapted for remote control and simple andcheap in manufacture. In accordance with this invention this is achievedby providing gripping jaws having planeparallel side surfaces, said jawsbeing supported in a cage allowing limited relative displacement of thejaws in a direction parallel to said side surfaces. Gripping jaws havingplane-parallel side surfaces are so cheap that it is not worth while tosharpen the gripping teeth of worn jaws, but it is cheaper to replaceworn gripping jaws by new ones. The sets of jaws inserted into a cagemay properly be engaged and disengaged from the rod or pole by remotecontrol, this possibility being of particular importance where drivingforces in opposite directions are required.

It is another object of this invention to provide a driving-jackequipment or assembly allowing combination of different types of unitsto form jacks of different operating characteristics. For this purposethe jack equipment broadly comprises a cylinder and a piston relativelydisplaceable by means of pressure fluid and connected each to a grippinghead, a guiding extension at one end of said cylinder for guiding atubular piston rod extend- 3,347,522 Patented Oct. 17, 1967 ing throughsaid guiding projection, a casing having an end wall connected to theouter end of the piston rod with an annular space formed between saidcasing and piston rod, an end of said casing opposite said end wallbeing guided at the outside of said guiding extension, a free end faceof said guiding extension in said annular space, and a pressure springinserted between said end wall of the casing and said free end face ofthe guiding extension. As an example, a driving jack adapted to producedriving forces in opposite directions is obtained when a double-actingactuating unit is combined with gripping heads including gripping jawsengageable and disengageable by remote control.

This invention will now be explained in detail with reference to theattached drawings wherein FIG. 1 shows a complete driving jack partiallyin elevation and partially in section,

FIG. 2 shows a double-acting actuating unit,

FIG. 3 shows a double-acting gripping head adapted for remote control,

FIG. 4 is a single-acting gripping head adapted for remote control,

FIG. 5 shows a set of gripping jaws in section,

FIG. 6 is a top view of the set of FIG. 5 and FIGS. 7 to l0.showmodified sets of gripping jaws.

The jack shown in FIG. 1 serves for lifting a load, for instance aworking platform, a slip form of the like along a rod or pole 1. Thejack has a cylinder 2 to which a pressure fluid may be admitted throughconnection piece 3. A piston 4 fixed to or made in one piece with atubular piston rod 5 is inserted into the cylinder 2 and is axiallydisplaceabie therein. The free lower'end of the piston rod isinterconnected with a cylindrical mantle 7 by means of a threaded sleeve6 having a threaded flange. An adjustable stop ring 8 is screwed to theupper end of the mantle 7. The stop ring 8 is adapted for cooperationwith a stop ring 9 screwed to the lower end of a cylindrical extension44 of cylinder 2. A pressure spring 10 is inserted between the stop ring9 of the cylinder 2 and the radial flange of the sleeve 6.

An upper gripping head 11 is screwed to the upper end of cylinder 2,wherein gripping jaws 35 engage the upper conical portion of the innersuface of the gripping head 11 with their inclined wedge surfaces 12.The construction of the set of gripping jaws will be explained in detailbelow. A pressure spring inserted between a ring 17 screwed into andforming the bottom of the grip ping head 11 and a base portion of theset of gripping jaws maintains the wedge surfaces 12 of the grippingjaws in contact with the conical surface portion 13- of thegripping-head casing.

A similar gripping head 18 is screwed to the lower end of the mantle 7,this lower gripping head 18 being thus operatively connected to thelower end of the piston rod 5 by means of the mantle 7 and the sleeve 6.Parts of the gripping head 18 are similarly designated as correspondingparts of the upper gripping head 11 and no further explanation isrequired. A ring 19 of the lower gripping head 18 serves as a supportfor the load to be connected to the jack.

The driving jack shown in FIG. 1 operates as follows: In the positionshown in FIG. 1 no pressure is admitted to the cylinder 2 so that thecylinder is maintained in its upper end position relatively to thepiston 4 by pressure spring 10, this upper end position being determinedby abutment of the ring 9 against the ring 8. The upper gripping head 11is thus maintained in a lower end position relatively to the lowergripping head 18 by which the load is carried by wedging of its grippingjaws against the rod 1. Pressure is now admitted to the cylinder wherebythe piston 4 is lifted relatively to the cylinder 2. The full load mustnow be carried by the upper gripping head because the lower grippinghead with the load is lifted by the piston 4 interconnected with thelower gripping head by the piston rod 5, the sleeve 6 and the mantle 7.When the piston 4 has reached its upper end position, pressure is shutoff and the pressure fluid is allowed to flow back from the cylinderwithout pressure, whereby the load is again carried by the lowergripping head 18 while the cylinder and the upper gripping head 11areshifted upwardly by spring 10'until the ring 9 again abuts againstthe stop ring 8. By suitable adjustment of the stop ring 8 the liftingstroke per operating cycle of the jack may be adjusted to a desiredvalue. In this way it is possible to equalize the lifting stroke of anumber of lifting jacks acting simultaneously on the same load, forinstance a slip form. The adjustable stop ring 8 as well as the otherparts of the actuating mechanism or unit, viz. thecylinder 2 and thespring 10, are relatively easily accessible for maintenance orreplacement. Moreover. these parts are perfectly protected against waterand contamination by the tubular piston rod and parts 6 and 7 connectedthereto separating them from the rod 1 so that humidity andcontaminations cannot penetratae into the actuating mechanism from therod 1.

The driving jack of FIG. 1 is able to produce forces in one directiononly. The load must be connected to the lower gripping head 18 and theload can only be pulled but not pushed upwardly because the uppergripping head 11 can only be lifted by the limited force produced byspring 10.

However, when a double-acting cylinder of the type shown in FIG. 2 isused instead of the single-acting cylinder of FIG. 1, the jack shown inFIG. 1 will produce pushing and pulling forces in the same order so thatthe load may be connected to the lower or upper gripping headas desired.The double acting actuating unit shown in FIG. 2 has an external threadat its upper end for screw-connection with the upper gripping head 11.The lower end of the piston rod 5, not completely shown in FIG. 2, isconnected to themantle 7 in the manner shown in FIG. 1. The piston 4a isdisposed below the upper end of the piston rod, and sealing rings areprovided ateach side of the piston and at each end of the cylinder.Connecting pieces 3a and 3b respectively are provided at each end of thecylinder so that pressure fluid may be admitted alternatively to thelower or upper side of the piston. A driving jack assembled from adouble-acting actuating unit according to FIG. 2 and of upper and lowergripping heads 11 and 18 as shown in FIG. 1 operates as follows: Thelower end position of piston 4a as shown in FIG. 2 corresponds to theposition shown in FIG. 1 wherein the piston is also shown in its lowerend position. In this case the cylinder 2a with the upper gripping head11 connected thereto is in an upper relative end position and the. loadis carried by the lower gripping head. Pressure is now admitted to thelower connection piece 3a whereby the piston 4a and the parts connectedthereto are lifted relatively to the cylinder 2 and the up-. pergripping head 11. The load is now carried by the upper gripping head andthe. lower gripping head with the load connected thereto is pulledupwardly. At the end of the stroke, pressure is admitted to the upperconnection piece 3b whereby the cylinder and the upper gripping head 11are lifted.

If the load is connected to the upper gripping head, this head carriesthe load when the jack is in the initial position'as shown in FIG. 2.Pressure is now admitted to the lower connection piece 3a whereby thelower gripping head is pulled upwardly by the piston 4a. At the end ofthe stroke pressure is admitted to the upper end of the cylinder,whereby the upper gripping head is lifted relatively to the lowergripping head, the load is now carried by the lower gripping head andthe upper gripping head with the load connected thereto is pushedupwardly.

When a double-acting jack able to produce forces in opposite directionsis wanted, the double-acting actuating 4 unit shown in FIG. 2 iscombined with gripping heads as shown in FIGS. 3 and 4. :As shown inFIGS. 3 and 4 these gripping heads have suitable internal and externalthreads for connection to the cylinder 2 or 2a and to the mantle 7..

The upper gripping head shown in FIG. 3 has a cylindrical casing 20forming the outer wall of an annular cylinder. By means of a ring 22 aninner cylindrical mantle 21 is connected to the outer mantle 20.Pressure fluid may simultaneously be admitted to the lower and uppercylinder space through a connection piece 23 and bores of the ring 22.Annular pistons 24 and 25 having each a conicalcontrol surface 26 areaccommodated in the upper and lower half of the cylinder. Sets ofgripping jaws 35 are inserted in opposite positions into each end of thegripping head 20, the structure of these sets of gripping jaws beingshown in detail in FIGS. 5 and 6. Each of the sets of gripping jaws hasa cage 27 with an axial bore 28 having a diameter slightly exceeding thediameter of the rod 1. The cage has an upper portion 29 having the shapeofa truncated cone and a cylindrical lower portion 30. Thecagehas sixradial slots 31 with plane-parallel side surfaces, extending from theupper end of the cage to a relatively thin'base portion of the cage.

An annular groove .32 is cut between the upper conical portion and thelower cylindrical portion of the cage, this groove receiving an openring of a spring wire 33. This wire 33 passes through openings 34 of thegripping jaws 35. These jaws have plane-parallel side surfaces and areheld with little clearance in the slots 31. The gripping jaws have atoothing 36 at the inner edge surface and inclined outer wedging edgesurfaces, the inclination of the wedging surfaces corresponding to theinclination of the conical control surfaces 26 of the pistons 24 and 25.Since the diameter of the wire 33 is smaller, than the di ameter of theopenings 34 of the jaws 35, limited displacement of the jaws 35 in axialand radial direction is possible so that such jaws may properly beclamped against the rod 1 and may also be disengaged from thesame. Thesets of gripping jaws shown in FIGS. 5 and 6 are particularlyadvantageous: in thatthe gripping jaws. having plane-parallel surfacesmay be produced at such low costs that sharpening of the toothing 36does not pay and worn jaws may simply be replaced by new ones. Replacingof the jaws is very simple because it is only necessary to Widen thewire sufficiently for axially removing it from the groove 32, whereafterthe jaws 35 may be stripped 0d the wire and new jaws may he slid ontothe wire which is then inserted into the groove 32 after insertion ofeach jaw into a slot of the cage.

The upper set of gripping jaws of FIG. 3 abuts against a cap nut 38 andthe lower set of gripping jaws 27 abuts against the face 39 of the ring40 of the cylinder 2a screwed to the upper gripping head.

The lower gripping head 41 shown in FIG. 4 is similar to the uppergripping head 20 shown in FIG. 3, but it has only a single-actingcylinder operable by means of pressure fluid admitted through aconnection piece 42 and a conduit not shown. The piston 43 of thiscylinder has a similar conicalzcontrol surface 26 for acting on themclined wedge surfaces 37 of the set of gripping jaws 27. The set ofgripping jaws 27 abuts against a threaded ring screwed into the lowerend of the mantle 41 of the gripping head.

The driving-jack equipment having a double acting actuating unit-asshown in FIG. 2 and an upper and lower gripping head as shown in FIGS. 3and 4 respectively operates as follows:

If the piston 4a with the lower gripping head 41 connected thereto is inits lower end position shown in FIG. 2, pressure is admitted to theupper gripping head 20 whereby both pistons 24 and 25 are pressedagainst the associated sets of gripping jaws. 27 and the jaws 35 areclamped against therod 1. The upper gripping head is thus locked on therod. 1 in both directions due to the opposite positioning of the sets ofgripping jaws. No pressure is admitted to the lower gripping head 41 sothat the jaws 35 of this head are disengaged from the rod 1. Pressure isnow admitted through connection piece 3a below piston 4a so that thispiston is lifted together with the lower gripping head 41 which isdisengaged from the rod 1. When the piston has reached its upper endposition, pressure is admitted to the lower gripping head 41 wherebythis head is again locked on the rod 1 and then pressure is removed inthe upper gripping head 20 so that this head is disengaged from therod 1. Pressure fluid is now admitted through connection piece 3b abovethe piston 4a whereby the cylinder 2a with the upper gripping head 20connected thereto is lifted. Hereby it is important that the upper setof gripping jaws of the upper gripping head 20 is disengaged from itsactuating piston in order to prevent automatic wedging of the jawsagainst the rod. It is thus necessary to connect the upper set ofgripping jaws to the cup nut 38 or to the mantle 20 by any suitablefixing means not shown in FIG. 3 in order to allow proper disengagementof the piston 24 from the gripping jaws associated therewith. When thecylinder has reached its upper end position as shown in FIG. 2 thepressure admittance to the gripping heads is reversed again as explainedabove, and another operating cycle or stroke of the jack begins.

The advancing direction of the jack along the rod 1 may be reversed byreversing the cycle of pressure admittance to the gripping heads, thisneeding no further explanation. The same forces may be obtained in bothdirections when the forces acting downwardly are produced by thegripping head 20 (FIG. 3) having two oppositely directed sets ofgripping jaws. In this case the load should be connected to the lowergripping head 41. Otherwise, that is when no or limited forces indownward direction are required, the load may be connected to any one ofthe heads 20 or 41. With the double-acting cylinder shown in FIG. 2 thespring may be omitted.

The actuating units shown in FIGS. 1 and 2 are suitable for control withoil or water. The units are suitable for operation with water due to thefact that the cylinder 2 is completely separated from the casingenclosing the spring 10. The piston rod is guided in a relatively longguiding extension 44 of the cylinder whereby it is extremely improbablethat water would leak through the sealing ring of the piston rod andalong the latter into the spring casing.

Instead of a screw fixture betwen the actuating units and the grippingheads a bayonet joint may be used. The sets of gripping jaws and theassociated springs 16 may be supported on or may be connected to diskssimilar to the ring 17 (FIG. 1), such disks being removably mountedbetween the actuating units and the gripping heads without screw fixing,whereby exchange of worn sets of gripping jaws is further facilitated.Opposite ends of each spring 16 may be attached to such a disk and tothe cage 27 of the associated set of gripping jaws respectively.

In the embodiment shown in FIG. 7 the gripping jaws 135 and the cage 127have an annular groove 136 in their upper portion and a wire ring 137 isinserted into the groove 136 for preventing tilting of the jaws inwardlyinto the bore of the cage, whereby insertion of the rod 1 into the jackcannot be hindered by tilted gripping jaws.

In the embodiment shown in FIGS. 8 to 10 the gripping jaws are preventedfrom tilting by cams or ribs 237 projecting from the side surfaces ofthe slots 231 of the cage 227 and engage grooves 236 of the jaws 235.Since the radial width of the grooves 235 exceeds the radial width ofthe cams 237 limited axial displacement of the gripping jaws in the cageis possible so that the jaws may always be clamped against the rod 1independently of differences in the dimensions of the rod 1. A smallpressure spring 238 inserted into a recess of the base of the cage 227acts on each of the gripping jaws for continuously maintaining each jawin contact with the conical surface 13 and with the rod 1 respectively.

A similar arrangement is possible with grooves corresponding to grooves236 in the side walls of the slots of the cage and with ribscorresponding to ribs 237 on the side surfaces of the gripping jaws.

What is claimed:

1. A driving-jack equipment for stepwise advancing of a load along asupport, comprising a cylinder and a piston relatively displaceable bymeans of pressure fluid, gripping heads on each of the cylinder andpiston, said piston having a tubular piston rod, a guiding extension atone end of said cylinder for guiding said tubular piston rod extendingthrough said guiding projection, a casing having an end wall connectedto the outer end of the piston rod with an annular space formed betweensaid casing and piston rod, an end of said casing opposite said end wallbeing guided at the outside of said guiding extension, a free end faceof said guiding extension in said annular space, and a pressure springinserted between said end wall of the casing and said free end face ofthe guiding extension.

2. An equipment according to claim 1, comprising a guide ring on saidcasing slidably engaging the outer surface of said guiding extension andaxially adjustable on said casing, and a stop ring connected to the freeend of the guiding extension, said guide ring and stop ring constitutingan adjustable stop means for limiting the relative displacement of saidcasing and guiding extension respectively.

3. A driving-jack equipment for stepwise advancing a load along asupport, comprising a cylinder and a piston relatively displaceable bymeans of pressure fluid, and a gripping head connected to each saidcylinder and piston in surrounding relation to said support, each ofsaid grip ping heads having at least one set of gripping jaws disposedaround said support and having plane-parallel side surfaces, an innertoothed gripping surface and an outer wedging surface, each saidgripping head having a conical wedging surface outside said outerwedging surface of the respective gripping jaws, each said headincluding an annular cage cooperative with said jaws and having radialslots with plane-parallel surfaces, said gripping jaws being movable insaid slots with their plane-parallel side surfaces adjacent said slotplane-parallel surfaces to enable said jaws to be radially wedgedbetween said wedging surface and said support.

4. An equipment according to claim 3, wherein said cage includes aportion having the shape of a truncated cone, the inclination of saidconical wedging surface, said wedging surfaces of the gripping jaw-s andof said cage portion being equal, and said wedging surfaces of thegripping jaws engaging said conical wedging surface outside said cageportion.

5. An equipment according to claim 3, wherein each of said gripping jawshas at least one bore and said cage has at least one annular groove, ananchoring wire ring extending through said bores of all gripping jaws ofa set of gripping jaws and the annular groove of said cage.

6. An equipment according to claim 5, wherein said cage has an annulargroove at the inside and an annular groove at the outside therof, and ananchoring wire ring in each said groove.

7. An equipment according to claim 3, comprising a double-actingcylinder, a first gripping head having two sets of gripping jaws actingin opposite direction and engageable by remote control, and a secondgripping head having one set of gripping jaws engageable by remotecontrol, positive advance being possible in each direction along saidsupport due to said double-acting cylinder and said first gripping head.

'8. An equipment according to claim 3, wherein cams and groovesextending in axial direction of said cage and interlocking with radialclearance are provided at said plane-parallel side surfaces and in saidslots of the cage respectively for preventing tilting of said grippingjaws in References Cited UNITED STATES PATENTS Rigby.

Vreeland 24-2635 Lignoski 24263.5 Mitchell 24-2635 Thompson.

Alexander.

Von Heidenstam et a1.

Anderson 24263.5

Gustafsson 254106 Jansen 25429 X FOREIGN PATENTS Denmark.

OTHELL M. SIMPSON, Primary Examiner.

3. A DRIVING-JACK EQUIPMENT FOR STEPWISE ADVANCING A LOAD ALONG ASUPPORT, COMPRISING A CYLINDER AND A PISTON RELATIVELY DISPLACEABLE BYMEAN OF PRESSURE FLUID, AND A GRIPPING HEAD CONNECTED TO EACH SAIDCYLINDER AND PISTON IN SURROUNDING RELATION TO SAID SUPPORT, EACH OFSAID GRIPPING HEADS HAVING AT LEAST ONE SET OF GRIPPING JAWS DISPOSEDAROUND SAID SUPPORT AND HAVING A PLANE-PARALLEL SIDE SURFACES, AN INNERTOOTHED GRIPPING SURFACE AND AN OUTER WEDGING SURFACE, EACH SAIDGRIPPING HEAD HAVING A CONICAL WEDGING SURFACE OUTSIDE SAID OUTERWEDGING SURFACE OF THE RESPECTIVE GRIPPING JAWS, EACH SAID HEADINCLUDING AN ANNULAR CAGE COOPERATIVE WITH SAID JAWS AND HAVING RADIALSLOTS WITH PLANE-PARALLEL SURFACES, SAID GRIPPING JAWS BEING MOVABLE INSAID SLOTS WITH THEIR PLANE-PARALLEL SIDE SURFACES ADJACENT SAID SLOTPLANE-PARALLEL SURFACES TO ENABLE SAID JAWS TO BE RADIALLY WEDGEDBETWEEN SAID WEDGING SURFACE AND SAID SUPPORT.